package com.yxym.collection;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

public class Collection_ {
    @SuppressWarnings("all")
    public static void main(String[] args) {
        //Collection
        //Map
        //1.集合主要有两组(单列集合 双列集合)
        //2.Collection 有两个重要的接口List Set ，实现子类都是单列集合
        //3.Map接口的实现子类是双列集合，存放的K-V
        ArrayList arrayList = new ArrayList();
        arrayList.add("");
        arrayList.add("");
        HashMap hashMap = new HashMap();
        hashMap.put(" " ," ");
    }
}
